Apparatus for treating cast materials in the molten state

ABSTRACT

An apparatus is disclosed for treating materials in the molten state. Bubbling gas mixtures and reactants are introduced beneath the surface of the molten material in the riser of the cast to provide an exothermic reaction and delay the solidification of the riser.

United States Patent Wiener 1 Dec. 30, 1975 [541 APPARATUS FOR TREATINGCAST 3,010,820 11/1961 Graefct al. 266 34 T x MATERIALS [N THE MOLTENSTATE 3,137,753 6/1964 Feichtinger 3,521,695 7 1970 Diener 164/55 1Inventor: Llvw Wlener. 105-40 62nd a 3,760,862 9/1973 Van Goudoeveretal. 164 55 Forest Hills, NY. 11375 [22] Filed: Jan. 8, 1975 PrimaryExaminer-Francis S. Husar l l PP N04 539,274 Assistant Examiner-Gus T.Hampilos Related Us. Application Data Attorney, Agent, or FirmPhilip D.Amins [62] Division of Ser. No. 381,510, July 23, 1973, Pat. No.

521 US. Cl. 164/338; 164/53; 164/55; [57] ABSTRACT 164/122; 266/34 T[51] Int. Cl. B22D 7/10; B22D 27/00 An apparatus is disclosed fortreating materials in the [58] Field of Search 164/53, 55, 71, 122, 336,molten state. Bubbling gas mixtures and reactants are 164/338; 266/34 T,34 A introduced beneath the surface of the molten material in the riserof the cast to provide an exothermic reac- [56] References Cited tionand delay the solidification of the riser UNITED STATES PATENTS2,525,973 10/1950 Sundstrom et a1. 266/34 T 4 Claims, 7 Drawing Figures5/ 5e 57 s t o 32 Z O o 40 4 l US. Patent Dec. 30, 1975 Sheet 2 of33,929,185

US. Patent Dec. 30, 1975 shw 3 of 3 3,929,185

APPARATUS FOR TREATING CAST MATERIALS IN THE MOLTEN STATE y The presentapplication is a division of my prior U.S. Pat. application Ser. No.381,510, filed July 23, 1973, 5 now U.S. Pat. No. 3,882,922.

BACKGROUNDOF THE INVENTION I The present invention relates to anapparatus for treating cast materials, and in particular, to anapparatus for bubbling gas mixtures and dipping the reactants beneaththe surface of the molten material to delay the solidification thereofand to remove deleterious materials therefrom.

Several inventions of which I am aware, attempt to obtain a uniformcasting without deleterious materials or shrink defects, but none haveproven tobe entirely satisfactory. Oxidant gas and reactant materialshave been introduced at various times and pressures to the surface ofthe molten material in an attempt to slow the setting of the moltenmaterial so that a uniform impurity free cast object would result. Thepresent invention overcomes the problems of the prior art by providingan automatic means which can be applied to any ingot or mold that isfilled with a molten material alloy from a common down sprue.

The present invention further insures rapid oxidation of a highlydeoxidant agent by the stirring or agitating of the top portion of acast riser by the submersed insertion of the deoxidant agent. Thiscauses an exothermic reaction maintaining the riser molten after thecast body has solidified. The present invention may be used with anymixture-of one or more highly deoxidant agents combined with a formingslag agent which forms compounds that constitute a fluid slag over thesurface of the molten material within the riser that is thermallyinsulated' from the atmosphere.

The gas that is introduced beneath thesurface of the molten material isunder predetermined pressure, causing bubbling therein, and may beoxidant or inert in nature depending upon the type of treatment .to beapplied to the molten material. Hereafter, the term oxidant gas isintended to encompass both pure oxygen and mixtures of inert gas andoxygen.

An object of the preseritxinvention is to transfer the heat from anexothermic reaction to the top of a casting riser thereby improvingdirectional solidification of a casting or ingot avoiding shrinkage orsegregation defects. I I

Another object of the present invention is to save molten alloy by usingrisers of decreased size by introducing an exothermic reaction into theriser to delay the solidification thereof. I Y

A further object of the present invention is to modify the chemicalcomposition, structure or remove deleterious constituents from a moltenalloy by bubbling an inert gas through. reactants submerged beneath thesurface of the molten alloy.

. An additional object of the present invention is to combine the gasand'reactants beneath the surface of the molten alloy material by anapparatus therefore. SUMMARY OF THE PRESENT INVENTION surplus of heat todelay the solidification of the upper portion of said cast body to avoidsegregation and shrinkage defects.

An apparatus for treating a molten metal cast body according to theprinciples of the present invention comprises: reservoir means forstoring a prescribed amount of reactant to be introduced below thesurface of the molten metal, the reservoir means being provided with abottom opening and inlet and outlet ducts for introducing the reactant,a refractory plunger adapted to be affixed beneath the reservoir means,the

plunger including a reaction chamber having an upper opening adapted tocooperate with the reservoir means lower opening and adapted to beimmersed in molten metal, an injection plunger slidably mounted forvertical movement within the opening, the injection plunger being hollowand having upper, middle and lower portions, the upper portion beingprovided with means adapted to introduce gas under pressure, the middleportion being provided with a circular shaped flange adapted to seal theopening, the lower portion being provided with a frusto conical headadapted to seal the opening when in its uppermost. position and adaptedto release the reactant when lowered therefrom, the head being porousand adapted to be inserted beneath the surface of the molten metal andbubble said gas therethrough, and means for mounting and lowering therefractory plunger to the surface of the molten metal and the injectionplunger beneath the surface of the molten metal.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects,features and advantages of this present invention will become moreapparent from the detailed discussion hereinafter when considered inconjunction with the accompanying drawings wherein: FIG. 1 is apictorial representation, taken in partial vertical section, of a moldriser adapted to cooperate with an apparatus utilizing the principlesand method of the present invention;

FIG. 2 is an enlarged pictorial representation, taken in verticalsection, of the lower and middle portions of the apparatus shown in FIG.1 in its initial position priorto the treatment of a molten alloy;

FIG. 3 is an enlarged pictorial representation of the apparatus of FIG.1 at the point or release of the reactant into a moltenalloy;

FIG. 4 is an enlarged pictorial representation of the apparatus of FIG.1 with a gas injection plunger bubbling gas beneath the surface of amolten material to cause an exothermic reaction in a riser;

FIG. 5 is a greatly enlarged view taken in elevation of the lowerportion of the injection plunger;

FIG. 6 is a pictorial representation of the apparatus of FIG. 1including a frame and roller means for moving the apparatus of FIG. 1 tothe risers of a plurality of molds; and

FIG. 7 is a pictorial representation of the apparatus of FIG. 1including a modified frame suitable for use with an ingot mold riser.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the figureswherein similar reference characters indicate similar parts in theseveral figures of the drawings and, in particular, where the numeral 10generally refers to an apparatus suitable for treating cast materials inthe molten state. The apparatus includes an adjustable supporting frame11 mounted on a cope l2 and surrounds molding box 13. The cope 12 isprovided with a riser cavity 14 whichis filled with a molten material15. The size of the cavity 14 may vary according to the size of theriser or surface 16 of the molten material or metal alloy 15. In contactwith the surface 16 of the metal alloy is a refractory plunger 17 whichis provided with a circular flange 18 into which is inserted aconventional electric detector 19 and a thermocouple 20 for monitoringthe temperature of the molten alloy in the riser. The plunger 17includes a reaction chamber formed by a casing 26 which is provided withan opening or feeding hole 27.

The casing 26 is affixed to a reservoir or feeding chamber 28 formed bya casing shell 33 which is additionally provided with a lower opening 29adapted to cooperate with an opening 27 in the casing 26, an inlet duct30 which is used to feed the reactants 31 there through, in aconventional manner, and an exhaust or outlet duct 32. Attached to theshell 33 is a vibrator 34 which functions to remove molten alloy or slagfrom the refractory plunger as will be explained hereinafter.

The shell casing 33 is affixed to a housing 35 which is provided with alower opening and an upper opening 41 in a base 42 and a cap 43,respectively, which are in a vertical line. The cap 43 has affixedtherein guide rods 44 whose length may be adjusted by means adjustingnuts 45.

The upper portion 46 of frame 11 is provided with holes 47 which areadapted to receive guide rods 44. In addition, the upper portion 46 hasaffixed thereto one end of an air cylinder 48. The other end of the aircylinder 48 has a suspension hook 49 which may be used by a crane, notshown, to position the apparatus 10.

Centrally located in the openings 41 and 40 is injection duct 50, whichis provided with an input duct 51 and pressure regulator 52, which isadapted to be coupled, via a flexible pressurized hose 53, to aconventional sourceof oxidant gas, not shown.

The upper portion of injection duct is adapted to be affixed to aplunger rod 54 of the air cylinder 48. A

first collar 55 is provided on injection duct 50 which functions as alimit stop of the injection duct 50 for upward movement. A second collar56 is provided on injection duct 50 below the first collar 55. Thesecond collar 56 is adapted to cooperate with a return spring 57 toraise the injection plunger 50. The first collar 55, and the secondcollar 56 and spring 57 are all within the housing 35. A circular plug58 is provided on the injection duct 50 within the feeding chamber 28and is adapted to seal opening 40 in the housing 35 when the injectionduct 50 is at its uppermost position. The lowermost portion of theinjection duct 50 is provided with a frusto conical plunger 59 which hasa refractory porous plug 60 inserted in the refractory base 61 thereof.

When the injection duct 50 is in its lowermost position plug 58 sealsopening 27 pushing the reactants 31 into the molten material 15 andplaces the plunger 59 beneath the surface of the molten material 15. Asnoted earlier the depth of insertion of the plungers l7 and 19 may bevaried by adjusting the effective length of travel of guide rods 44 byadjusting nuts 45.

Referring now to FIG. 2, which shows an enlarged view of the apparatus10 and its operation thereof after the reactants 31 have been introducedinto the feeding chamber 28, via inlet duct 30. The refracting plungerl7 and injection plunger 59 are both in their uppermost position so thatopening 40 is sealed by plug 58 and openings. 27 and 29 are sealed bythe frusto conical injection plunger 59.

FIG. 3 shows the apparatus 10, after the air cylinder 48 has beenpressurized and starts lowering the injection duct 50 thereby openingholes 27, 29 and 40 permitting the feeding of the reactants 31 to themolten material 15. The injection plunger 59 may be maintained in thisposition for as long a time as is necessary, consistent with thetreating of the molten material allowing the reactants to reach thedesired temperature. The gas may be permitted to flow through plunger 59before plunger 59 reaches the surface of the molten material 15, andcontinued thereafter. During treatment the electronic vibrator 34increases the stirring effect by its vibrations and prohibits theadhering of reactant particles or slag to the plungers 17 and 59.

There are two critical temperatures that are preferably monitored whiletreating the molten material 15 in accordance with the principles andapparatus of the present invention. The first critical temperatureoccurs when the reactants 31 contact the surface of the molten material,since the reactants initially withdraw heat therefrom. The temperatureof the molten material, however, is still sufficient for a reaction tooccur between the gas, reactants and molten material. Thus, the secondcritical temperature occurs subsequent to the introduction of thereactants, and this temperature determines the timing of the injectionof the plunger 59 beneath the surface of the molten material. Thesetemperatures are determined experimentally, as well as the optimum timefor submerging plungers 59 and 17 beneath the surface of the moltenslurry consistent with the amount of treatment to be given thereto.

FIG. 4 shows the moment when the exothermic reaction is fully developedand reaction chamber 25 is completely closed by plug 58. The bubbles ofgas under low pressure pass through the refractory porous plug 60penetrating the slurry of molten alloy 15 and reactants 31. Theresulting slag and gases rise on the surface of the plunger circularflange 18 of the plunger 17. The fluid slag as a result of this reactioncompletely covers the surface of the riser 14. The injection of gas isterminat'ed when the plunger 59 is removed from the slags surface. Thelength of time that the plunger 59 is kept below the surface of themolten material 15 is related to the size of the riser, type of moltenalloy, reactants, treatment to be given, and may be a variablecontrolled by the increase of temperature in the upper part of the riser14, as measured by thermocouple 20.

FIG. 5 is an enlarged cross sectional view of the frusto, conicalplunger 59 showing the injection duct 50, refractory porous plug 60 andrefractory base 61, mentioned earlier.

v FIG. 6 illustrates a vertical view in elevation of the apparatus 10being affixed to a carriage 62 with rolling beams 63 being positionedabove an automatic pouring conveyor 64. To increase the treatinghandling capacity of the conveyor a plurality of apparatus 10 may beincorporated on an endless belt or supporting rollers may be used tomove the molding box or boxes below the apparatus 10.

FIG. 7 shows a modified frame adapted for use with an ingot riser 66,and includes adjustable supporting legs 67 which may be made to conformwith the size of the riser 66 associated with an ingot mold.

Hereinbefore has been disclosed a method and an apparatus for practicingsaid method for obtaining improved castings and reduced waste materialassociated therewith by introducing reactant materials and bubblinggases beneath the surface of the molten material to delay the settingthereof.

It will be understood that various changes in the details, materials,arrangement of parts and operating conditions which have been hereindescribed and illustrated in order to explain the nature of theinvention may be made by those skilled in the art within the principlesand scope of the present invention.

What is claimed is:

1. An apparatus for treating a molten metal cast body comprising:

a. reservoir means for storing a prescribed amount of reactant to beintroduced below the surface of said molten metal, said reservoir meansbeingprovided with a bottom opening and inlet and outlet ducts forintroducing said reactant;

b. a refractory plunger adapted to be affixed be'neath' said reservoirmeans, said plunger including a reaction chamber having an upper openingadapted to cooperate with said reservoir means bottom opening andadapted to be immersed in molten metal; an injection plunger slidablymounted for vertical movement within said reservoir means and saidreaction chamber, said injection plunger being hollow and having upper,middle and lower portions, said upper portion being provided with meansadapted to introduce gas under pressure to 6 said molten metal, saidmiddle portion being provided with a circular shaped flange adapted toseal said upper opening when said injection plunger is lowered into saidmolten metal, said lower portion being provided with a frusto conicalhead adapted to seal said upper opening when said head is in itsuppermost position and adapted to release said reactant when loweredtherefrom, said head being provided with a porous opening thereinadapted to be inserted beneath the surface of said molten metal andbubble said gas therethrough; and d. means for mounting and loweringsaid refractory plunger to the surface of said molten metal and saidinjection plunger beneath the surface of said molten metal. 2. Anapparatus for treating a molten metal cast body according to claim 1further including vibration means adapted to be affixed to saidreservoir means for preplungers.

1. AN APPARATUS FOR TREATING A MOLTEN METAL CAST BODY COMPRISING: A.RESERVOIR FOR STORING A PRESCRIBED AMOUNT OF REACTANT TO BE INTRODUCEDBELOW THE SURFACE OF SAID MOLTEN METAL, SAID RESERVOIR MEANS BEINGPROVIDED WITH A BOTTOM OPENING AND INLET AND OUTLET DUCTS FORINTRODUCING SAID REACTANT; B. A REFRACTORY PLUNGER ADAPTED TO BE AFFIXEDBENEATH SAID RESERVOIR MEANS, SAID PLUNGER INCLUDING A EREACTION CHAMBERHAVING AN UPPER OPENING ADAPTED TO COOPERATE WITH SAID RESERVOIR MEANSBOTTOM OPENING AND ADAPTED TO BE IMMERSED IN MOLTEN METAL; C. ANINJECTION PLUNGER SLIDABLY MOUNTED FOR VERTICAL MOVEMENT WITHIN SAIDRESERVOIR MEANS AND SAID REACTION CHAMBER, SAID INJECTION PLUNGER BEINGHALLOW AND HAVING UPPER, MIDDLE AND LOWER PORTIONS, SAID UPPER PORTIONBEING PROVIDED WITH MEANS ADAPTED TO INTRODUCE GAS UNDER PRESSURE TOSAID MOLTEN METAL, SAID MIDDLE PORTON BEING PROVIDED WITH A CIRCULARSHAPED FLANGE ADAPTED TO SEAL SAID UPPER OPENING WHEN SAID INJECTIONPLUNGER IS LOWERED INTO SAID MOLTEN METAL, SAID LOWER PORTION BEINGPROVIDED WITH A FRUSTO CONICAL HEAD ADAPTED TO SEAL SAID UPPER OPENINGWHEN SAID HEAD IS IN ITS UPPERMOST POSITION AND ADAPTED TO RELEASE SAIDREACTANT WHEN LOWERED THEREFROM, SAID HEAD BEING PROVIDED WITH A POROUSOPENING THEREIN ADAPTED TO BE INSERTED BENEATH THE SURFACE OF SAIDMOLTEN METAL AND BUBBLE SAID GAS THERETHROUGH; AND D. MEANS FOR MOUNTINGAND LOWERING SAID REFRACTORY PLUNGER TO THE SURFACE OF SAID MOLTEN METALAND SAID INJECTION PLUNGER BENEATH THE SURFACE OF SAID MOLTEN METAL. 2.An apparatus for treating a molten metal cast body according to claim 1further including vibration means adapted to be affixed to saidreservoir means for preventing molten metal and slag from adhering tosaid refractory plunger and said injection plunger.
 3. An apparatus fortreating a molten metal cast body according to claim 1 wherein saidmounting and lowering means includes a roller means for successivelypositioning said plungers over a plurality of molding casts.
 4. Anapparatus for treating a molten metal cast body according to claim 1wherein said mounting and lowering means further include compressed airmeans and return spring means for controlling the lowering of saidplungers.